/Engine/Plugins/Developer/Concert/ConcertUI/ConcertSharedSlate/Source/ConcertSharedSlate/Public/Session/History/SSessionHistory.h
Optional. If bound, invoked when generating a row to add an overlay to a column.
WidgetArgsType & OnMakeColumnOverlayWidget &40; const SConcertSessionActivities::FMakeColumnOverlayWidgetFunc & InDelegate &41;